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Tuesday, 20 December 2016

What is Native Data Types in Cassandra Database

Native Data Types

CQL support following native types that are below

Data Type
Constants supported
Description
ascii
string
ASCII character string
bigint
integer
64-bit signed long
blob
blob
Arbitrary bytes (no validation)
boolean
boolean
true or false
counter
integer
Counter column (64-bit signed value)
date
integer, string
A date (with no corresponding time value)
decimal
integer, float
Variable-precision decimal
double
integer float
64-bit IEEE-754 floating point
float
integer, float
32-bit IEEE-754 floating point
inet
string
An IP address, either IPv4 (4 bytes long) or IPv6 (16 bytes long). Note that there is no inet constant, IP address should be input as strings
int
integer
32-bit signed int
smallint
integer
16-bit signed int
text
string
UTF8 encoded string
time
integer, string
A time with nanosecond precision
timestamp
integer, string
A timestamp (date and time) with millisecond precision
timeuuid
uuid
Version 1 UUID
tinyint
integer
8-bit signed int
uuid
uuid
A UUID
varchar
string
UTF8 encoded string
varint
integer
Arbitrary-precision integer

I am going to describe some native data type

Counters:-
The counter data type is used to define counter columns whose value is a 64-bit signed integer and counter support operations i.e. incrementing and decrementing.

Example:-
A= A+ 3 is used to increment/decrement counters. The column name after the ‘=’ sign must be the same than the one before the ‘=’ sign.
UPDATE User
   SET total = total +200
   WHERE userid = 1012
    

Important limitations of Counters
  • Counter cannot be used for PRIMARY KEY columns of a table.
  • Either all the columns of a table outside the PRIMARY KEY have the counter type, or none of them have it.
  • Counters do not support expiration.
  • The deletion of counters is supported
  • Counter updates are, by nature

Timestamps data type

Timestamp data type values are encoded as 64-bit signed integers representing a number of milliseconds. Timestamps can be enter or input in CQL either using their value as an integer, or using a string.
All of the values below are valid timestamp values for Mar 2, 2011, at 04:05:00 AM, GMT:

1299038700000
'2011-02-03 04:05+0000'
'2011-02-03 04:05:00+0000'
'2011-02-03 04:05:00.000+0000'
'2011-02-03T04:05+0000'
'2011-02-03T04:05:00+0000'
'2011-02-03T04:05:00.000+0000'


Times data type

Times data type values are encoded as 64-bit signed integers representing the number of nanoseconds since midnight. A time can be input either as an integer or using a string. The format of times is hh:mm:ss[.fffffffff].


All of the values below are valid times values
'08:12:54'
'08:12:54.123'
'08:12:54.123456'
'08:12:54.123456789'

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